Material for records



Patented Feb. 29,. 1944 MATERIAL FOR RECORDS Harald Mediger, Dessau,Germany: vested in the Alien Property Custodian NoDrawing. ApplicationJune 8, 1040, Serial N0. 339,491 In Germany June 22, 1939 3 Claims.

This invention relates to a base material for Gramophone records andother sound 'records and to the manufacture of same, said recordsbearing on one or both surfaces mechanical sound registrations in formof grooves cut into the material by means-of a stylus according to theEdison or to the Berliner method, as disclosed in U. S. P. 272,786granted November 8, 1887.

It is known to manufacture Gramophone records and sound records on filmstrips from synthetic materials consisting of vinyl polymers.

Compared with Gramophone records manufactured from Celluloid and shellacmixtures, such records have the advantage of being less fragile andchemically more resistant. They are true to scale, but also have thedisadvantage of being thermoplastic and become useless already atrelatively low temperatures, for instance slightly above 100 C.

A number of other artificial materials not possessing thesedisadvantages are not suited for sound records on account ofdifliculties arising during the manufacturing process.

It is an object of the invention to provide a new and more suitable basematerial of the above mentioned type for the manufacture .of soundrecords, especially Gramophone records.

A further object is to provide a base material highly resistant towardswear and tear and atmospheric influences.

A further object is the provision of an unbreakable material for saidrecords.

These and other objects will become apparent from the followingdescription.

The present invention is based on the observation that Gramophonerecords and other carriers for sound recording are most advantageouslymanufactured from linear synthetic condensation products, forinstancesuperpolyamides, superpolyesters, superpolyethers, superpolyanhydrides,superpolyacetals, polyureas, polyurethanes, polyhydrazidesl Such basematerial for sound records possesses excellent hardness in the finishedstate, which increases the resistance towards wear and tear and reducesthe surface noises to a minimum. Such records are unbreakable,chemically very resistant and, generally speaking, not at all sensitivetowards atmospheric influences, for instance moist air. Also theirresistance towards higher temperatures is excellent.

The'se carriers for sound recording according to the present inventionmay be obtained by casting, if necessary centrifugal casting, bypressing, forming or dye-casting. The Gramophone records may be embossedby pressing in according to U. S. Patents Nos. 2,071,250, 2,071,-

251, 2,071,252, 2,071,253. Also the polyamides according to U. S. Patentapplication Ser. No. 220,266, filed July 20, 1938, now Patent No.2,241,- 321 granted to Paul Schlack and the polyamides and polyurethanesaccording to U. S. Patent application Ser. No. 277,948, filed June 7,1939, by Emil Hubert, Paul Schlack and Herman Ludewig, may be employed.As suitable examples of polyureas are those produced in Example 4 and ofa suitable polyurethane is that produced in Example 9 of the lastmentioned patent application. Example 4 reads as follows:

13 grams of octamethylene-diurethane (CH3.O.CO.NH.(CH:) a.NH.C0.0CH3)and 6 grams of hexamethylene diamine are heated for two hours at 240 to250 C. in an open glass vessel while ammonia is introduced in vaporform. There is formed a viscous mass which solidifies on cooling andyields a whitish-yellow hem-like resin, which possesses the property ofbeing capable of ybeing drawn out into fibers. After a further heatingfor 5 to 7 hours at 240 to 250 C. the resin is suitable for spinning. Itsoftens between 195 and 200 C.

The resins obtained in the same manner from octamethylene diurethylaneand octa-methylene diamine or from octamethylene diurethylane andethylene diamine show similar properties. They are light-yellow togreenish in color, have a hornlike appearance and soften at about 225and 200 C. respectively. Hexamethylene-diurethane or ethylene-diurethanelikewise'yleld resinous condensation products together with diamines."

Example 9 reads as follows: 5 grams of octamethylene diurethylane(CH3.O.CO.NH. (CH2) aNH.C0.0CHa) and 1.5 grams of l.6 -hexanedio1 areheated in an atmosphere of nitrogen four hours at 220 and subsequentlyat 250 C. A white hard resin results after cooling.

To the substances mentioned above plasticizers, fillers, pigments andthe like may be added. Film strips for sound recording consisting oflinear synthetic polycondensation products may be oriented by colddrawing which increases their tenacity considerably.

I claim:

1. A sound record bearing mechanically produced registrations of soundon at least one of its surfaces and consisting essentially of a linearsynthetic condensation product having a crystalline structure of thegroup consisting oi superpolyamides, polyureas, and polyurethanes.

2. A Gramophone record in disc shape bearing mechanically producedregistrations of sound on at least one or its surfaces and consistingessentially of a linear synthetic condensation product having acrystalline structure of the group consisting of superpolyamides,polyureas, and polyurethanes.

3. A sound record in the form of a film strip bearing mechanicallyproduced registrations of sound on at least one oi its surfaces andconsisting essentially of a linear synthetic condensation product havinga crystalline structure of the group consisting oi superpolyamides,polyureas,

and polyurethanes.

HARALD MEDIGER.

